Fluid treating apparatus



c. L. HOWSE ET AL FLUID TREATiNG APPA RATUS Oct. 18, .1938.

"Filed March 30, 1953 4Shets-Sheet 1 74am cs ((6 MY/r, P

Oqt. 18 1938; c. HOWSE ET A1.

FLUID TREATING APPARATUS 4 Sheets-Sheet 2 Filed March so, 1955 a n-$ 21M Mama: 7

Oct. 18, 1938. L: HOW E ET AL 2,133,819

FLUiD TiREATING APPARATUS Filed March 30, 19:53 4 Sheets-Sheet s 4 Sheets-Sh e t 4 V Oct. 18; 1938.

V c. 1.. HOWSE' ET AL FLUID TREATING APPARATUS Filed March 50; 1935 Patented a. is,

ramp ramrmo arraaa'ros Curtis L. Howse, Detroit, Harry E. Brelsi'ord, Birmingham, and Samuel F. Cox and Willis P. Thomas, Highland Park, Mich, assignorsto Diamond Power -Specialty Corporation, Detroit, Mieln, a corporation of Michigan Application March 30,

22 Claims.

which includes elements disposed in the path of the fluid to be treated and means for moistening the surfaces of these elements.

One 'of the primary objects 0! this invention is to provide in an apparatus of the above mentioned character means for neutralizing the effect of the velocity of the fluid to be treated on the liquid flowing over the elements disposed in the path of the flow of the fluid. More particularly, the invention contemplates the provision of means ior preventing the fluid flowing through the passage from blowing the liquid on the elements to the rear faces of the elements. I A'iurther object of this invention isto provide in an apparatus of the above mentioned character, means for effecting an even distribution of.

the maximum amount of moistened surface for contact by the fluid to be treated.

The invention further contemplates the prov vision in an apparatus of the above mentioned character of means for reducing .to a minimum the amount of liquid necessary to keep the surfaces ofthe elements moistened to the desired degree.

Numerous other objects and advantages of this invention will become more apparent as the following description proceeds, particularly when reference is had to the accompanying drawings,

wherein:

Fig. 1 is a semi-diagrammatic vertical sectional view through a gas treating apparatus constructed in accordance with the teachings of this section showing a further modified form of ele ment;

Fig. 5 is a view similar to Fig. 3 and partly in a; section showing a iurther form of baiiie element;

1933. Serial No. 663,608 (c1. ze1--112) Fig.6 is a view similar to Fig. 3 partly in section showing a further form of baille element;

Fig. '7 is a view similar to Fig. 3 and partly in section showing a still further form ofbaiile element;

Fig. 8 is a rear elevational view in section of a further form of baiiie element;

Fig.'9 is a sectional view taken the line 9-9 of Fig. 8;

Fig. 10 is a sectional view similar to Fig. 9 showing a further modified form oi construction;

Fig. 11 isa view similar to Fig. 9showing a still further modified form of construction;

Fig. 12 is a view similar toFig. 1 showing a further modified form oi baiiie element;

Fig. 13 is a fragmentary horizontal sectional view through one of the elements shown in Fig.

substantially on Fig. 14 is an enlarged sectional view through a further modified form of element; 0

Fig. 15 is a view similar to Fig. 1 showing a still further modified form of construction; 1

. Fig..16 is a horizontal sectional view through the structure shown in Fig. '15;

Fig. 17 is an enlarged elevational: view of a slightly modified form of baflle element;

Fig. 18 is a semi-diagrammatic view similar to Fig. 1 but showing a mechanism for automatically adjusting the inclination of the baiile elements;

Fig. 18 is a fragmentary sectional view taken substantially on the line 19-" of Fig. 18;

Fig. 20 is a view similar to Fig. 1 showing a control means for the supply of the wetting medium;

Fig. 21- is a view similar to Fig. 20 showing a slightly modified arrangement of parts;

Fig. 22 is a sectional view through a gas treating apparatus showing a further modified form of baiile element;

Fig. 23 is a fragmentary sectional view taken substantially on the line 23-23 of Fig. 22;

Fig. 24 is a view similar to Fig. 1 showing a further modified form of construction;

Fig. 25 is a view similar to Fig.20 showing a modified form of control means for the supply of the wetting medium; and I Fig. 26 is a view similar to Fig. 25 showing a further modified arrangement of parts.

In its broader aspects the present invention is directed to a means for eiiecting a contact betweena fluid and a liquid. The means for accomplishing this preferably comprises a casing in which a plurality of baflie elements are mounted together with means for moistening the surfaces of these elements by flowing a liquid over the same. The fluid to be treated enters one end 68 end thereof, having contacted with the moistened surfaces of the baiiie elements during its passage 'through the'casing. The fluid to be treated may be dust laden gases such as are discharged from boilers, industrial furnaces and the like, or may be air. If the fluid to be treated is a dust laden gas, the device functions as a deduster, the dust particles and the like in the gas being trapped in the liquid onthe surfaces ofthe elements so that the gas ismoistened and cleaned before it is discharged from the casing. If the fluid to be treated is air which is to be humidified, the air during its passage through the casing becomes moistened with the moisture on the bailieelements so that the air is discharged from the casing moistened to a desired degree with a suitable liquid such as water.

To facilitate the description of the invention, the word gas will be utilized to designate the fluid whichis caused to flow through the casing to be cleaned and/or moistened. The term gas", therefore, is to be construed as meaning air, furnace gases, or other fluids. Further, the term "liquid" will be used to designate the substance which is utilized to moisten the outer surfaces of the baiile elements. When the device is utilized as a deduster, this liquid will have suitable dust collecting characteristics, while if the device is to be utilized as a humidifier, this liquid will have suitable humidifying characteristics. Thus the term liquid" is to be construed as meaning either a dust collecting liquid, a humidifying liquid, or any liquid which will serve the particular purposes desired when brought in contact with the gas to be treated. Still further, the term "moistening'is to be construed as meaning "wetting or the application of a liquid to any desired degree".

Heretofore, in apparatuses of the above described character, use has been made of baille elements arranged in the path of the gas flow, means being provided for flowing a treating liquid downwardly over the outer surfaces of these bailie elements. In constructions of this character, dimculty has been encountered in obtaining an even distribution of the treating liquid over the surfaces of the baflle elements. One cause of this difliculty has been that the gas flowing through elements and contemplates further the provision the casing in which the baille elements are mounted has blown the liquid around to the rear faces of the baflle elements, with the result that thebaiiie elements be moistened, for the reason that the gas flrst contacts the front faces of the elements. The present invention contemplates the provision of means for insuring an even distribution of the liquid over the surfaces of the baflle of means to compensate for the tendency of the gas to blow the liquid around to the rear faces of the baine elements.

In the drawings wherein like reference characters designate corresponding parts throughout all views, several embodiments of the inventive .idea are disclosed. In Figs. 1 and 2 there is disclosed a construction which comprises a-casing 20, this casing providing a chamber 2| in which baille elements designated generally by the reference character 22 are located. The casing is shown as being mounted in a flue designated by the reference characters 23 and 24. The portion 23 of the flue is connected to a furnace or source of supply of the gas to be treated, while the portion 24 is connected to a suitable stack or other discharge for the treated gases. It will be understood that the gases in the portion 22 of the flue will enter'rthe chamber 2|, be treated therein by contact with the wetted surfaces of thebaiile elements 22 and will be discharged from the chamber by way of the'portion 24 of the flue. While the baiiie elementsmay be arranged within the chamber 2| in any desired manner, they are preferably, as illustrated in Fig. 2 of the drawings, staggered with reference to each other so that the gases passing through the chamber will contact fully with the elements. A guard 22' is preferably provided in the upper part of the chamber and in advance of the bailie elements to prevent the gas from passing over the tops of the elements.

The baiile elements 22 are supported on beams 25 which extend transversely of the chamber 2|, these beams being so disposed that they support the bailie elements above a hopper-shaped chamber 28 formed in the lower part of the casing 20. A conduit 21 provides a discharge for the chamber 28, this conduit being provided with any suitable valve designated by the reference character'28.

For effecting a. flow of the treating liquid over the outer surfaces of the baiiie elements, the

following structure may beprovided. Disposed above the casing is a reservoir which is supplied with a suitable liquid by a supply pipe 3|. Passing through the top wall of the casing and extending into the reservoir to receive liquid from the same are nozzles 32, these nozzles being arranged to discharge'the liquid into the open tops of the bailie elements. The baille elements are preferably hollow and are open at their tops and are inclined with reference to the vertical. It will be noted that the baflle elements are so inclined that the upper ends thereof lean toward-the entrance portion 23 of the flue, .or in other words,

the bai'iie elements are inclined in a direction opposite to the direction of gas flow. This inclination of the bailie elements may be effected either' by sloping the upper surfaces of the supporting beams or by suitably mounting the supporting beams for rotative adjustment so that the baiiie elements may be inclined to any desired angle. It will be understood that the nozzles 32 flt loosely within the open upper ends of the baflle-elements so that some latitude in the angle of inclination of the baflle elements is afforded. Further, the guard 22 preferably extends downwardly sumciently far to prevent the gases from passing over the tops of the baflle elements even when the latter are inclined to the greatest degree. If it is not desired to make the beams 'rotatively adjustable to thus vary the angle of inclination of the baffle elements, the elements are preferably fixed at an angle proportioned to the velocity of the gas flow, or if the velocity of the gas flow is variable, some intermediate angle may be selected.

With the elements inclined in this manner, it

aisaeio will be apparent that gravity will tend to cause the liquid flowing down the outer surfaces of the baiile elements may be smooth, if desired, and the elements may be made of any desired material, such as earthen material, either dense or porous, vitreous material, or any desired metallic material. 9

It will be understood that in operation, if the device is utilized as a humidifying device, the gas flowing through the casing will contact with the moistened surfaces of the baiiie elements and will absorb some of the liquid thereon so that the gas will leave the chamber 2 I properly humidified.

If the device is used as a dedusting apparatus, the dust laden gases passing through the chamber will contact with the moistened surfaces of the baflie elements, and the liquid on the battle ele' ments will collect the dust particles, the dust laden liquid flowing downwardly into the'hopper 28.

From the hopper the dust laden liquid may be discharged by way of the conduit 21. The gasesafter the dust particles have been removed from the same will leave the chamber in a cleansed and moistened condition by way of the portion 24 of the flue.

In Fig. 3 a slightly modifled form of construction is disclosed in which the baffle element 22* is shown as being provided with a helical thread 35 cut in its outer surface. The treating liquid flows down the surface of the baille element by way of the helical thread, and the baiile element is so inclined as to overcome the tendency for the wetting medium to flow around to the rear of the bailie element or to blow ofl the baiile element by reason of the gas velocity.

It will be apparent that with a right hand thread on the baille element, the effect of the inclination of the element is to increase the slope of Experiments have indicated that a baiiie ele- .ment such as that above described, if positioned vertically in thechamber 2 I will lose considerable liquid due to the gas velocity blowing theliquid of! of the element. Further, experiments have shown that the baflle element will have a greater I amount of the liquid on its rear face than on its front face. If, however, the bame'element is inclined to the proper angle, no liquidwh'atever is blownpfl' of the bailleelement, and the distribution of the liquid on the front of the element is practically identical with that on the rear face thereof. Thus the inclination of the bailie elements provides for the even distribution of the liquid over the surfaces of theelements, thus reducing the quantity of treating liquid utilized and rendering the element'more efhcient as a contact device. v

The inclination of the baffle elements has the amount of liquid.

than is provided by vertical elements of the same shape. Since the elements may be threaded with a minimum lead axially, manufacturing costs are decreased to a minimum and the element may be maintained in a-clean 'As in the first described form of construction, the baiile, elements 2fare preferably hollow. In this embodiment of the inventlon,'however, liquid is supplied to the interiors of the elements by nozzles 36 which project into the baille elements through sealed openings in the lower ends thereof.

These nozzles may, as illustrated, be connected to suitable supply headers 31 associated with the beams 25' in any desired manner.

further advantage of providing more moistened surface in a limitedarea, since in a-;given height, a greater area is provided by inclined elements condition with a small Itmight'be noted that by supplyingthe liquid to the lower ends of the elements, a more even temperature of the elements is maintained when the fluidto be treated is hot furnace gas. By supplying the cooler liquid to the inside part of the baiiie element which is last reached by the liquid flowing over the'outside of the baflle element, the latter is kept relatively cool, and losses by evaporation of the liquid are minimized.

In Fig. 4 of the drawings a further modified form of construction is disclosed as comprisinga bafiie element 22 having grooves "formed in its outer surface. As illustrated, these grooves are relatively deep, and the baiiie element is so inclined that the liquid will tend to flow in the grooves toward the front of the baiile element where it is most needed. In this embodiment the ballle element is shown as being solid, and there is disclosed a nozzle 29 for discharging the liquid on to the upper end of the baiile element. It will be understood, however, that the baflle element be supplied to the same either from above or below as desired.

In this embodiment ofthe invention, the

grooves will function not only to aid in maintain- 'ing the liquid at the ,front of the baffle elements,

but will function also to increase to a substantial extent the moistened surface available for contact with the gas. A periodic flushing of the baffle element: will function to clean the grooves or troughs.

In Fig. 5 a further modified form of construction is disclosed in which the baflie element 22 is shown ascomprising a center shaft 4| and means providing a spiral path 42 of substantial width and to present a large amount of moistened surface. It will be obvious that the radial extent of the spiral as well as the longitudinal travel of the spiral for each 360 thereof can be varied to suit conditions. The baflle elementis preferably arranged so that the top thereof is inclined toward the gas flow to neutralize the effect of the gas velocity on the liquid in the helical trough. The means forming the spiral trough'is preferably so arranged as to provide a small angle designated from the top or the bottom thereof in any desired sage 43 which may be supplied with liquid either manner (not shown). The core is provided at spaced points with radially extending bores 44 which communicate with the central bore 43 and which provide means for feeding the liquid to the spiral trough at spaced points throughout the length thereof. By thus feeding the liquid to the trough at spaced points, the liquid is prevented from becoming too thick or heavy because of the dust collected by the same. While the means forming the helical trough is shown as being in the nature of a spiral fin integral with the core 4|, it will be apparent that this trough might be formed by a plurality of separate helical ringsJ As in the previously described form of construction, the element may be made of metal or ceramic material, or other suitable substance.

In Figs. 6 and 7 further forms which the grooves may assume are illustrated. In Fig. 6 there is disclosed an element 22 having a spiral thread on the outer surface thereof. In Fig. 7 there is disclosed a construction in which the baiiie element 22' has a multiple thread 46 on its outer surface. In each instance the liquid may be caused to travel downwardly over the outer surface of the element, the threads or grooves providingnot only an increased moistened surface, but providing also a means for slowly conducting the liquid downwardly throughout the length of .the heme elements.

In Figs. 8 and 9 a further modified form of construction is disclosed in which the rear face of the baiiie element 22 is provided with grooves 5|, these grooves inclining from a high-midpoint in substantially the center of the rear of the baille element downwardly toward the front face of the element. The front face of the element may be smooth, as clearly illustrated in- Fig. 9 of the drawings. 7

With the construction disclosed in these figures, it will be apparent that the liquid flowing down the exterior surface of the element will be conducted to the front side or face of the element to replace the liquid which is blown to the rear face of the element by the gas flowing through the chamber in which the elements are mounted. The elements may, asillustrated, be hollow and the dust collecting liquid fed to the same in any desired manner (not shown).

In Fig. 10 there is disclosed a construction quite similar to that shown in Figs. 8 and 9, in which construction, however, the grooves II are carried almost entirely around the elements 22 With the grooves extended in the manner disclosed in this figure, it will be apparent that only a small area of the front face of the element is'smooth.

In Fig. 11 the baflle element 22' is shown as being provided with the grooves II" which tend to return the liquid to the front face of the element. In this construction, however, the front face of the element is fluted orrcorrugated, as indicated by the reference character I, so as to make the liquid cling more tenaciously to this face of the element.

In each of the several forms of construction Just described, it will be apparent that the slope or inclination of .the grooves which carry the wetting medium from the rear to the front face of the element may be made any angle desired. The angle of slope of the grooves will preferably be proportioned to the velocity of the gases im'pringing against the face of 'the baflle element. These constructions provide for aselfi'estoring distribution of the wetting medium over the surfaces of the bailie elements to uniformly aisaaio maintain the moistened condition on the surfaces of the elements and to thus keep efficient as liquid contact devices.

In Figs. 12 and 13 there is disclosed a modified form of construction in which bailie elements 22" are shown as being mounted in a casing 20* In this modified form of construction, each baffle element is preferably supported in a vertical position by a suitable beam ""At being understood that the baifle elements will be so arranged that the gas flowing through the casing will contact the baflie elements.

In this modified form of construction the baffie elements are hollow, and a pipe is disposed centrally of each baiiie element. Each pipe extends within its respective element to a point adjacent the lower end thereof, and each pipe is supported within its element adjacent the upper end thereof by a spider 56. The pipes all extend upwardly into a reservoir 30*, so that the liquid in thisreservoir may flow downwardly into the bailie elements. It will be apparent that the liquid will circulate downwardly through each tube II, out the lower end of this tube, and then upwardly between this tube and the inner surface of the element. then overflowing the top of the element.

In this form of construction the outer surface of the element is shown as beingfiuted or corrugated, and the open top of the element is also preferably fluted or notched to facilitate the flow of the wetting medium from the interior of the element over the top edge of the same and down the corrugations on the outer surface of the-element.- Normally, the wetting medium would flow in a narrow stream down the center of each corrugation on the, baille element, but under the influence of the moving gas stream, the water in each corrugation is spread out into a thin fllm in the manner clearly illustrated in Fig. 13. The width of the corrugations is proportioned to the velocity of the gas stream, and

the corrugations may be either uniformly spaced or may be wider on the rear'face of the baflle element than on the front face thereof.

With this construction it will be apparent that the gas passing around the baille element will not wipe or blow the liquid of! of the surface of the element. Further, it will be apparent that with the element surface corrugated or fluted in the manner disclosed, a greater dust collecting surface will be obtained. Still further, the corrugations onthe surface of the element are of considerable assistance in disturbing the gas going over the surface of the element creating a turbulence which causes the dust particles held by the gas to come into contact with the wetted' surfaces on the element.

In Fig. 14 there is disclosed a baiile element 22" which comprises a central tube upon which are threaded circular spools. or the like 6|. The spools are spaced apart in any desired manner, as for example, by the projections 62, and the tube is provided with openings by which a-treating liquid from the interior of the tube may be discharged into the space between the spools. The arrangement is such that a liquid supplied to the interior of tube 60 in any desired manner will be discharged in a thin film between the spools to flow outwardly over the surfaces thereof.

The spool pieces may be made of any desired material such as earthen material, either dense or porous, a vitreous glazed material, metal, or any particular substance desired. A home elethe elements ment formed .in this manner will present a submay be so arranged that the major axes of the spools are offset with respect to each other, as indicated in the drawings.

In Figs. 15 and 16 a further modified form of'construetion is disclosed as comprising a casing 2| arrangedin a flue 22 and 24", this casing providing a chamber 2|. in which the baiile elements 22 are located. These baiile elements are in the form of plates, and they are arranged in staggered relation and at an inclinationto the direction of thegas flow, as clearly illustrated in Fig. 16'of the drawings. The angle of inclination maybe any angle desired, dependent upon the velocity of the gas.

The battle elements are preferably hollow, and nozzles 65 are provided for discharging a liquid from the reservoir 30" into the interiors of the elements. This liquid will fill the elements, and overflowing the tops thereof, will flow down the surfaces of the elements in the vertical grooves 66 formed thereon. The arrangement is such that the outer surfaces of the baflle elements will be entirely moistened so that they will act efllciently as liquid contact elements. a

In Fig. 17 there is disclosed a slightly modified form of baflie element which may be substituted for those shown in Figs. 15 and 16. It will be noted that the element which is of flat platelike construction-is provided on its outer surface with grooves Ill, these grooves being inclined to the horizontal. The grooves may, if desired,,

be inclined downwardly toward the direction of gas flow so that a liquid flowing down the surfaces of the-elements will be caused to traveltoward the front edges of the elements. The

- will be relatively small so as to utilize the effect of surface tension of the liquid in more thoroughly filling the grooves and exposing a greater wetted surface than would be the case if the grooves were relatively large or wide.

As previously stated, it is desirable that the inclination of the baille elements be proportioned to the velocity of the gas to be treated. In constructions where the gas velocity is constant or substantially so, the baflie elements may be permanently inclined at a desired angle. Where the velocity of the gas stream varies, however, it is desirable t8 provide some means for varying the inclination of the baille elements as the velocity of the gas stream varies. 1

An arrangement for accomplishing this result is shown in Figs. 18 and 19, in which figures, the reference character 20 designates a casing which provides a chamber 2| connected to the portions 23 and 24 of a flue. Disposed in the chamber 2 are bames 22, these baiilesbeing supported on the cross beams 25. These cross beams are provided on their ends with truunionsll suitably journaled in the side walls of the casing 20 and projecting exteriorly of the casing at one side thereof. Secured to the projecting ends of the trunnions are links 16, these links being connected at their free ends to a link." as by the pin and slot connections I8.- It will be apparent thatlongitudinal movement of link Fl will rock on their trunnions and to thus vary the inclination of the baiiie elements22. v

For effecting a longitudinal movement of the link 11 as the gas velocity varies, any suitable construction may be provided. By way of example, conduits II and 8| are shown as being tapped into the portions 28 and 24, respectively, of the flue. These conduits communicate at'their ends with a cylinder 82 in which a diaphragm '8 is mounted. -With the diaphragm arranged in this manner it will be understood that any variations in velocity of the gas in theflue will deflect the diaphragm. For example, if there is a velocity drop, the diaphragm will deflect to the left, while if the pressure is increased, the diaphragm will be deflected to the right. i i 1 Connected to thediaphragm I3 is a rod N which controls a suitable valve ll, this valve in turn controlling the admission of fluid under pressure. to a cylinder l. A piston (not shown) is located in this cylinder, and this piston is connected to the link 'Il to actuatethe same. with the construction disclosed, it will be apparent that as the gas velocity increases or decreases, the'link 11 will be actuated to incline the baille elements 22 to a greater or lesser extent, as desired. As brought out previously, the open tops of the baiile elements provide for the necessary movement of the baiile elements while still maintaining registration between the discharge end of nozzles 32 and the open ends of the baffle elements. It will be understood that any suitable means other than that disclosed might be provided for effecting an actuation of the link in dependence upon variations in v the velocity ofa gas stream, the embodiment disclosed being for the purposes of illustration only. In Fig. 20 there is disclosed a control means adapted more particularly for use when the construction is designed to operate as a humidifier. In humidifying apparatuses, the degree of wetness of the surfaces of the bailie elements should be varied as the 'moisture content of the gas stream varies. This may be accomplished by mounting a hygrostat 90 in the portion 23 of the flue, this hygrostat being of any suitable conthe-links litothus rotatively adlust thebeams its,

struction and being responsive to the humidity 1 -means SI for the valve 92, which valve is disposed in the conduit 3| which supplies the wetting medium to the reservoir 20.

. It will be apparent that the moistness of the bame elements will be dependent uponthe quantity of moistening medium supplied to the reservoir 30". Thus by providing the arrangement shown.'the amount. of wetting medium supplied to the reservoir and thus the amount of the wetting medium supplied to the baille elements may be varied in direct dependence upon the dryness of the air being supplied to the chamber 2|, with the result that regardless of the initial humidity of the air or gas, the gas will have the desired degree of saturation when it leaves the described form of construction,.this hygrostat is arranged 'to control the actuation'of a valve 02 which in turn controls the supply .of the melatonin: medium to the reservoir II. In both forms of construction it will be apparent that.

' provision is made to obtain a desired saturationof the gas regardless of the initial dryness of the gas to be humidified. While the hygrostats have been disclosed as being either in the inlet or outlet to the gas treating chamber, it will be apparent that if desired, hygrostats might be located both in the inlet and the outlet, to provide a dual control of the moistening medi to the reservoir.

In Figs. 22 and 23 there is disclosed a further form which the bailie elements may assume. These baiile elements, designated by the reference character 22', are located in the chamber 2], it being understood that they may, if desired, be staggered with reference to each other andmay be supported either vertically or inclined with, reference to the direction of gas flow, as previously described.

Each bame element comprisesa hollow tube formed withlongitudinally extending hollow protuberances II. The tube is twisted so that the protuherances DI extend spirallyaroimd the axis of the tube. -'Zlhus the protuberances provide spiral paths down the outer surfaces of the tubes, in which paths the moistening medium flows.

While the tubes may be formed in any desired manne they may, by way of example, be formed by drawing a cylindrical tube through a die to form longitudinally extending ho'llow ribs or the like on the tube. The tube is then twisted to arrange the protuberances spirally around the axis of the tube, it being understood that the tube may be twisted to any extent desired to thus obtain any desired pitch to the spiral paths thus formed. The ends of the tube may, if desired, be left circular, as illustrated, to facilitate the attachment of fiuid supply fittings to these tubes.

As illustrated, a moistening medium may be supplied to the lower ends of the baille elements by fittings 8. connected to a fluid Supply pipe '1,

The moistening medium will enter the lower ends of the elements, fiow. upwardly through the elements and overflow the open upper ends thereof. The overflowing moistening medium will now downwardly over the outer surfaces of the baille elements by way of the spiral paths formed by the spirally arranged hollow protuberances.

If desired, the moistening supply to the baffie elements may be located as illustrated in Fig. 24 of the drawings. By reference to this figure it will be noted that baiiie. elements 22', which are with the dust in the gases being deposited on the baille elements; The chamber 2 I is shown as being'provided'with a discharge conduit 21' adiaoent one side thereof by which the dustJaden liquid is discharged to any suitable point.

It constitutes a further feature of this invention to provide means for automatically controllihg the supply of the moistening medium 'to the bailie elements in dependence upon the temperature of the gases either entering or leav- 7s ing the gas treating chamber. Such a'construcaisasio tion is illustrated in m; as m which the numeral 2| designatu a gas treating chamber.

in which heme elements 22' are located. These baille elements may assume any of the forms previously described and may be supported either vertically or inclined, as desired. The-numeral 3| designates the supply pipe for the moistening medium, this supply pipe being shown as supplying the moistening medium to the reservoir 8|.

Located in the suppiypipeis a valve 02* which may be automatically actuated by a thermoresponsive element Ill-located in the portion 23' of the gas passage. The thermoresponsive element may be of any desired construction such as a thermocouple or the like, or may, as illustrated, be a closed container in which an expansible fiuid is trapped. This-container is shown as connected by a conduit III to a bellows or the like III, this bellows being directly con- I necied to the valve 22* to actuate the latter.

The arrangement is such that the thermoresponsive element is directly responsive to the temperature of the gases supplied to the gas treating chamber and provides means whereby the supply of moistening. medium to the reservoir and thus the supply to the baille elements will be varied as the temperature of the gases varies. Thus the valve 02 may be opened wider as the temperature of the gasesrises and may be moved toward closed position as the temperature of the gases decreases.

As brought out before, the thermoresponsive element may be mounted either in the inlet or the outlet of the gas treating chamber, .and mounting of this thermoresponsive element in the outlet of the gas treating chamber is shown in Fig. 28. In this figure the reference character 2| designates a .gas treating chamber in which baifle elements 22" of any suitable construction are located? Disposed in the portion 24" of the fiue is a thermoresponsive element III" which may, as illustrated, be in the form of a fiuid thermometer and may be connected by a conduit Ill to a bellows III". The bellows is directly connected to'the-valve 92 which controls the supply of moistening medium to the baflle elements by way of the supply conduit ll With this arrangement it will be apparent that when the gases leave the treating chamber at too high a temperature, thus indicating inadequate moistening thereof, the valve '2" will be opened further to supply more'moistening medium to the baiiie elements. Thus the fiow of the moistening medium may be directly controlled by the temperature of the gases leaving the gas treating chamber, with the result that the gases will be moistened sufiiciently to'maintain the temperature thereof at some predetermined desired degree.

While the thermoresponsive elements have been disclosed as either in the-inlet to or the outlet from the gas treating chamber, it will be apceive the moistening medium from a reservoir or directly by means of supply pipes, as'in certain of the embodiments of the invention disclosed. It will be apparent that in the embodiments where the moistening medium is supplied to the lower ends of thebaiiie elements,.that as the supply is increased, more of the moistening medium will overflow the upper ends of the elements to thus vary the degree of moistening of the outer surfaces of the elements.

From the above it will be apparent that the invention provides a dust collecting, humidifying or like device in which provision is made to neutralize the effect of the gas velocity on the wetted sin-races of the baiile elements. Utilization is j made 'of the force of gravity by inclining the elements so that the force of gravity tends to; cause the wetting medium to flow to the front faces of the baiiie elements. Utilization is also made of the increased area provided by grooving the surfaces of the elements so that in a'limited area a great amount of moistened surface is obtained. The invention provides for an even distribution of the moistening medium over the surfaces of the baflie elements and provides that a limited amount of the liquid will moisten the surfaces sufficiently to effect a desired treatment of the gases. Theinvention further provides means for insuring that the opposition to the tendency of the gas stream to blow the moistening medium oil! of the baflie elements willbe" entire surface of the grooves, thus exposing a greater wetted surface than would be the case if the grooves were relatively largeor wide. In fact. this principle is applicable to other forms of grooved or threaded elements disclosed.- It is, furthermore, a desirable feature of the invention to-proportionthe size of the grooves according to the surface tension of the liquid employed as a wetting or moistening medium. While the invention has been described with some detail, it isto be understood that the description is for the purposes of illustration only and is not definitive of the limits of the inventive idea. The right is therefore reserved to make such changes in the detailsof construction and arrangement of parts as will-fall within the purview of the attached claims. What we claim as our invention is: I 1. In an apparatus of the class described, a gas passage, an element in said. gas passage in the path of the gas flow therethrough, means for supplying a moistening medium to the entire outer surface of said element, and means for causing the moistening medium on the rear face of said sectional shape that a liquid may readily flow around the same means for supplying a moisten- I ing medium directly to the entire outer surface of the element, and means for supporting said element in. an inclined position whereby the threaded outer surface of said element.

moistening medium tends to iiowby gravity to one side thereof.

path of the gas flow therethrough, means for supplying a moistening medium directly to the entire outer surface of'the element, said element being of substantial thickness and of such a cross sectional shape. that should may readily flow around the same and means supporting said element in such an inclined position that the moletening medium tends to flow by gravity to the portion of the element that contacted bythe gas.

4. In an apparatus of the class described, a gas passage, a tubular element in said gas passage in the path ofthe gas flow therethrough, said element being of substantial thickness and of such a cross sectionalshape that a liquid may readily flow around the same, means for supplying a moistening medium to the interior-of the tubular elementv whereby the moistening medium overflowsthe top ofthe element and flows down the outer surface thereof, and means for supporting said element in an inclined position whereby the moistening medium tends to flow by gravity to one facethereof.

5. In an apparatus of the class described, a gas passage, a dust collecting element in said passage in thepath of the gas ilow therethrough, means for supplying a moistening medium to the entire outer surface of said element, means forsupporting said element in a position inclined with reference to the vertical, and means for adjusting-the angle of inclination of the element.

6. In an apparatus of the class described, a gas passage, an element supported in an inclined positionin said gas passage in the path of the gas flow therethrough, means to supply a moistening medium to the outer surface of the element, and means operating to adjust the angle of. inclination of the element upon changes in the velocity of the gas passing through the gas passage.

7. In an apparatus of the class described. a

gas passage, an element in said passage in the path of the gas flow therethrough, said element having its outer surface provided with closely .spaced grooves inclined with reference to the longitudinal axis of the element, and means for supplying a moistening medium to the grooved outer surface of said element. i

. 8. In an apparatus of the class described, a gas passage, an element in said passage in the path of the gas flow therethrough, said element being provided with a spiral groove in its outer surface, means supporting said element in an inclined position, and, means forsupplying a moistening medium to the grooved outer surface of said element.

9. In an apparatus of the class described, a

gas passage, an element in said gas passage disposed transversely of the path of the gas flow therethrough, the outer surface of said element being provided with multiple threads, and means for supplying a moistening medium to the 10. In an apparatus-of the class described, a gas passage, an element in said gas passage in the path of the gas flow therethrough, means substantially horizontal gas passage, an element in said gas passage extending substantially from the top to the bottom of the passage, and meansto apply a liquid to the outer surface of the element at the top thereof, said element being provided with a continuous spiral extending substantially from the top to the bottom thereof.

12. In an apparatus of the class described, a

disposed substantially vertical in said gas passage in the path of the gas flow therethrough, said element having protuberances extending spirally longitudinally thereof, and means for supplying a moistening mediumto the outer surface of the element.

-= 13. In an apparatus of the class described, a

gas passage, an element supported in aninclined position in said passage in the path of the gas flow therethrough,. means to supply a moistening medium to the outer surface of the element, and

:0 means for varying the angle of inclination of the u the liquid will form menisci from the ridge of element, said means being automatically operable in dependence upon the velocity of the gas flowing through the said gas passage.

14. In an apparatus of the class described, a gas passage, an element extending-in said passage in the path of the gas flow therethrough, and means for supplying a liquid to the outer surface of said element, the surface of said element being provided with means affording a continuous path of travel for said liquid substantially greater than liquid flow thereover. 16. In an apparatus of the class described, a

gas passage, an element in said passage in the path of the gas'flow therethrough, said element having its outer surface spirally grooved throughout its length, means for supplying liquid to said surface, and means for controlling said liquid supp yg 17. In an apparatus of the class described, a gas passage, means providing a threaded surface in the gas passage in the path of gas flow there.-

through, and means for supplying a liquid to said threaded surface, the size of the threads in said surface being so proportioned to the surface tension of the liquid supplied to the surface that each thread to the ridge of the next thread.

18. In an apparatus ofthe class described, a gas passage, means in said gas passage in the path of the gas flow therethroughprovidinga ai sasr'e threaded surface angularly disposed with reference to the horizontal, and means for supplyin a liquid to the threads at the upper end of said surface in such amounts that the liquid will not overflow the threads, the size of the .threads in the surface being so proportioned to the surface tension of the liquid supplied to the surface that the liquid will form menisci from'the ridge of each thread to the ridge of the next thread.

19. In an apparatus of the class described, a gas passage, an element in said gas passage in the path of the gas flow therethrough, said element having a grooved outer surface,. and means for supplying a liquid 'to the outer surface of said element to wet-the same, the grooves in said surface being relatively small whereby the surface tension of the liquid will cause the liquid in threads at the upper end of said element in such' amounts that the liquid will not overflow the spiral threads on the element, the size of the threads on said element being so proportioned to "the surface tension of the liquid supplied to the surface of the element that the liquid will form a meniscus from the ridge of each thread to the ridge of the next adjacent thread.

21. In an apparatus of the class described, a.

gas passage, a baiiie element in said gas passage in the path of the gas flow therethrough, and

means for supplying a moistening medium to the outer surface of the baflie element, the outer surface of the baiiie element being so grooved as to cause the moistening medium on the rear face of the baiile element to flow to the front face thereof.

22. In an apparatus of the class described, a substantially horizontal gas passage, a grooved "baiiie element disposed at an inclination to the vertical in said gas passage and in the path of the .gas flow therethrough, and means for supplying creased in the direction of gas flow past thev baiiie element. 

